This invention relates to the testing of printed circuit boards, and more particularly to the test probes that are used to make contact with the electronic circuitry on the circuit board. Test probes are basically made up of three parts: a plunger, a housing and a spring. The plunger and the spring are assembled into the housing and are held therein by crimping. When the test probe is assembled in this fashion, they are then typically inserted into a tubular receptacle which is mounted in an insulated board in a pattern that corresponds to the circuit pattern of the printed circuit board or other object being tested. Each receptacle is wired to a test set and with electronic circuits becoming more dense, it is becoming more and more common to find test probes mounted distances of a diameter apart with thousands of test points located on an insulated board which is referred to in the trade generally as a test fixture.
There may be electrical or mechanical failures in a probe or possibly tip damage thereto. This being the case, it is highly desirable that the spring probe be replaceable. Most of the probes now on the market are replaceable as an assembled unit; that is, the entire probe assembly has to be replaced by removing the same from the probe receptacle to which wiring is attached. It would be advantageous to eliminate the housing and still retain the ability to replace a probe contact. However, due to the closeness of the spacing of the probes as referred to above where the probes may be as closely spaced as 0.100 inch, it can be realized that this is an extremely delicate operation. As can be imagined, any attempt at repair must be arranged in a simple fashion to avoid damaging adjacent units. There is therefore a need for a test probe in which the plunger may be easily disassembled to replace the same should a failure occur, and also one which will exhibit a low electrical resistance.